Coupling for cryogenic media

ABSTRACT

A coupling for handling fluid media, preferably for cryogenic media or liquefied natural gas. The coupling has a single core or multicore coupling connector plug and a coupling socket, with associated ball valves. Rotating rings associated with the coupling connector plug and the coupling socket allow for opening and closing of the ball valves to permit transfer of fluids via a conduit that can extend into the coupling socket past the plane of separation.

BACKGROUND AND SUMMARY OF THE INVENTION

This application claims the priority of DE 101567405, filed Nov. 19,2001, the disclosure of which is expressly incorporated by referenceherein.

The invention relates to a coupling, particularly for cryogenic mediaand liquefied natural gas, having

-   -   a single-core or multicore coupling plug and a coupling socket.        When coupled, a conduit of the coupling plug, which is        constructed to be movable with respect to the coupling plug in        the axial direction, extends or can extend beyond the plane of        separation into the coupling socket.

The invention also comprises

-   -   a plug-side ball valve,    -   a socket-side ball valve,    -   the ball valves being constructed for the leading-through of the        conduit, and    -   devices for opening and closing the ball valves.

The invention also relates to the use of such a coupling.

In the following, the designations of special cryogenic medium will bepreceded corresponding to their state of aggregation by the letters “G”for “gaseous” and “L” for “liquid”; thus, for example, GH₂ or LH₂ forgaseous or liquid hydrogen respectively. Furthermore, the terms “CNG”and “LNG” are used for compressed or liquefied natural gas.

Hydrogen and natural gas are currently becoming more and moresignificant as energy carriers because of the rising demand for energyand increased environmental awareness. Thus, trucks, buses, passengercars and railroad engines are already driven by means of natural-gas orhydrogen-operated engines. Furthermore, first attempts are being made topower airplanes by means of the above-mentioned media.

The storage of the hydrogen or natural gas “on board” theabove-mentioned means of transport makes the most sense in liquid form.For this purpose, the hydrogen and LNG have to be cooled toapproximately 25 K. and 112 K. respectively and have to be maintained atthis temperature, which can be implemented only by correspondinginsulating measures at the storage containers or tanks. However, becauseof the low density of GH₂ and CNG, storage in the gaseous state in theabove-mentioned means of transport, as a rule, is less advantageousbecause the storage has to take place in large-volume, heavy storagetanks at high pressures.

German Patent Document DE-A 41 04 711 describes a conventional couplingof the above-mentioned type. The principle of such a coupling is basedon a system in which two ball valves—one on the plug side and one of thesocket side—are flanged to one another. Subsequently, a vacuum-insulatedfill pipe moves through the passage bores of the ball valves from theplug side, through which fill pipe the (cryogenic) medium flows to thesocket side of the coupling. After the filling operation, the plug movesback, and the ball valves are closed again. Subsequently, the mutualflanging of the ball valves is separated. A refueling coupling of thistype permits an overfilling of (cryogenic) liquids, while, on theoutside, a cooling of the visible components cannot be detected.

When applying the above-described principle, it is necessary to open orclose the plug-side ball valve and the socket-side ball valve by a90°-rotation of the balls. Conventionally, this actuating operation hasbeen carried out by a manual lever which—as normally used for ballvalves—opens or closes the ball by a 90°-rotation. By means of agearwheel drive, which engages when the coupling halves are connected,the socket-side ball valve is simultaneously opened or closed.

For automatic applications, for example, such as refueling by means of aso-called refueling robot, it becomes possible to actuate the plug-sideball valve by means of a hydraulic or pneumatic drive. The socket-sideball valve is opened in the same manner as during the manual operationby way of a gearwheel, which engages during the linking-up of thecoupling flanges.

However, based on the geometrical situations, the gearwheels in theaforementioned conventional coupling have to engage before the flangescontact one another. An exact mutual engagement of the teeth during thelink-up operation requires a very good axial guidance of the plug siderelative to the socket side. Because of the extremely limited spaceconditions, a guidance, such as a cone-type guidance, cannot be used inthe required form. A successful link-up operation therefore depends onthe skill of the operating personnel or on the sensor system and precisecontrol of the refueling robot.

Furthermore, during the link-up operation, the torsional axes of theball valves have to be situated in a plane, so that the teeth of thegearwheel drive also engage in a plane.

In addition, it has to be ensured that during the link-up, the tooth tipof one side engages in a tooth base of the opposite side. If two toothtips butt in front of one another, the flanges cannot be connected.

Also, as a result of their exposed arrangement, the gearwheels areexposed to considerable dirt contamination due to weather influences.Because of the narrow tolerances, which exist in the case of a toothing,any dirt contamination may lead to jamming of the gearwheels and toincreased wear.

It is an object of the present invention to provide a coupling of theabove-mentioned type, particularly for cryogenic media and liquefiednatural gas, which avoids the above-mentioned disadvantages.

This and other objects and advantages are achieved according to one ormore embodiments of the invention by a coupling valve where:

-   -   the devices for opening and closing the ball valves are        constructed as 1) a rotating ring which is assigned to the        coupling plug and can be displaced in the longitudinal direction        of the coupling plug, and 2) as a rotating ring which is        assigned to the coupling socket and is in an operative        connection with the socket-side ball valve; wherein    -   the rotating rings can be rotated about the longitudinal axis of        the coupling plug and the coupling socket;    -   the rotating rings have devices for the force-locking and/or        form-locking mutual connection; and    -   the rotating ring assigned to the coupling plug is in an        operative connection with the plug-side ball valve and/or an        arbitrary driving device is assigned to the plug-side ball        valve.

According to an embodiment of the invention, the two ball valves are notimmediately connected with one another or moved into an operativeconnection with one another during the connecting of the coupling plugand the coupling socket, but rather when the actual connection operationbetween the coupling plug and the coupling socket has already beenconcluded. Thus, the coupling flanges can first be connected with oneanother in the conventional manner, but without the possibility of anoccurrence of previous restrictions by an inexact axial guidance andmutual engagement of the pairs of gearwheels.

It is not necessary for the rotating ring assigned to the coupling plugto be constructed as a complete ring. On the contrary, it is sufficientfor this ring to consist of partial rings or partial ring bodies.

BRIEF DESCRIPTION OF THE DRAWING

The coupling according to the invention as well as further developmentsof the latter will be explained in detail in relation to the embodimentillustrated in the figure. The figure shows a perspective partialrepresentation of a possible embodiment of the coupling according to theinvention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The coupling has a plug-side flange 9 and a socket-side flange 10 whichare form-lockingly connected with one another by means of a clamping 8.The actual coupling operation between the coupling plug and the couplingsocket will be concluded when the clamping-together 8 of the two flanges9 and 10 has taken place.

According to the invention, the coupling has a plug-side rotating ring 3as well as a socket-side rotating ring 4. The two rotating rings 3 and 4can be rotated about the longitudinal axis of the coupling plug and thecoupling socket (illustrated by the two wide arrows). In addition, theplug-side rotating ring 3 can be displaced in the longitudinal directionof the coupling plug (illustrated by the narrow arrow). While theplug-side rotating ring 3 is in an operative connection with theplug-side ball valve 1, the socket-side rotating ring 4 is in anoperative connection with the socket-side ball valve 2.

However, the rotating ring 3 assigned to the coupling plug does not haveto be in an operative connection with the plug-side ball valve 1. In analternative embodiment, the plug-side ball valve 1 can be moved by anarbitrary driving device—such as, for example, another rotating ringwhich is independent of the rotating ring 3 assigned to the couplingplug, a hydraulic or pneumatic piston drive, or an electric-motor drive.In still another embodiment, the plug side ball valve 1 can beoperatively connected to both the rotating ring 3 and an arbitrarydriving device.

In an embodiment, if the coupling plug and the coupling socket or theirflanges 9 and 10 are clamped to one another (8) as illustrated in thefigure, the opening of the ball valves 1 and 2 takes place in that theplug-side rotating ring 3 is displaced by means of a defined advancingforce in the direction of the socket-side rotating ring 4. Preferably,the two rotating rings 3 and 4 have notches on their faces so that theycan be mutually connected in a form-locking and force-locking manner. Insuch an embodiment, the notches of the plug-side rotating ring 3 engagewith the notches of the socket-side rotating ring 4.

Now the plug-side rotating ring 3 is rotated about its longitudinal axisby the customer, the operating personnel and/or automatically. Thedefined advancing force is preferably maintained in this case. Here, thedisplacing and/or rotating movement of the plug-side rotating ring 3 cantake place by means of a hydraulic, pneumatic or electric drive.

If the two rotating rings 3 and 4 have already engaged, the socket-siderotating ring 4 is immediately rotated along as a result of theform-locking and force-locking. If no engagement exists yet between thetwo rotating rings 3 and 4 because, for example, the notch heads arematched up in front of one another, the plug-side rotating ring will atfirst rotate by a notch head width, without taking along the socket-siderotating ring. However, subsequently, the plug-side notch head willengage in the notch base of the socket-side rotating ring 4, if thedefined advancing force of the plug-side rotating ring 3 was maintained.The angle difference resulting from the above-described slightrotation—compared with the immediate engagement of the two rotatingrings 3 and 4—can be tolerated because of the minimal size of the angle.

The two rotating rings 3 and 4 are connected with ring gears 5 and 11,which are situated in an area of the respective connection side notvisible on the outside and protected from becoming dirty. Theabove-mentioned ring gears 5 and 11 drive the drive shafts 7 and 13 ofthe ball valves 1 and 2 by way of pinion gears 6 and 12.

A defined angular rotation of the rotating rings 3 and 4 thereforeresults in a 90°-rotation of the ball valves 1 and 2 or their ballsdefined by the transmission ratio of the ring gears and bevel gears.

In the embodiment of the coupling according to the invention illustratedin the figure, the two ball valves 1 and 2 are opened or closed in asynchronous manner. If the plug-side ball valve 1 is moved by means of adriving device other than the above-described driving device, thisplug-side ball valve 1 can be opened or closed also in an asynchronousmanner with respect to the socket-side ball valve 2.

As soon as the ball valves 1 and 2 are opened, the vacuum-insulated fillpipe 14 moves through the passage bores of the ball valves 1 and 2, andthe filling operation can start. After the termination of the fillingoperation, the fill pipe 14 is withdrawn and the ball valves 1 and 2 areclosed again in the reverse sequence. After the plug-side rotating ring3 has moved back again, the clamping connection 8 of the couplingflanges 9 and 10 can be opened up and the coupling plug and couplingsocket can thus be separated from one another.

As an alternative to the above-described notches, the rotating rings 3and 4 or their mutually abutting head sides may have a friction liningor friction linings. A conical construction of the head sides of therotating rings 3 and 4 is also conceivable. The torque required forrotating the balls of the ball valves 1 and 2 will then be transmittedby friction. The normal force (pressure force) required for this purposeis generated by way of the above-explained defined advancing force ofthe plug-side rotating ring 3.

The foregoing disclosure has been set forth merely to illustrate theinvention and is not intended to be limiting. Since modifications of thedisclosed embodiments incorporating the spirit and substance of theinvention may occur to persons skilled in the art, the invention shouldbe construed to include everything within the scope of the appendedclaims and equivalents thereof.

1. A coupling, comprising a single-core or multicore coupling plughaving a conduit constructed to be movable with respect to the couplingplug in an axial direction; a coupling socket, wherein when the couplingsocket is coupled with the coupling plug, the conduit of the couplingplug is capable of extending into the coupling socket beyond the planeof separation between the coupling plug and coupling socket; a plug-sideball valve and a socket-side ball valve, the ball valves beingconstructed for the leading-through of the conduit; a rotating ringassigned to the coupling plug, said coupling plug ring capable of beingdisplaced in a longitudinal direction of the coupling plug; and arotating ring assigned to the coupling socket, said coupling socket ringbeing in operative connecting with the socket-side ball valve, whereinthe rotating rings can be rotated about the longitudinal axis of thecoupling plug and the coupling socket, said rotating rings furthercomprising devices for forming force-locking or form-locking mutualconnections, and wherein said coupling plug ring is in operativeconnection with the plug-side ball valve or an arbitrary is assigned tothe plug-side ball valve.
 2. A coupling according to claim 1, whereinthe coupling is a coupling for passage of cryogenic media or liquefiednatural gas.
 3. A coupling for cryogenic media according to claim 1,wherein the rotating ring assigned to the coupling plug comprisespartial rings or partial ring bodies.
 4. A coupling for cryogenic mediaaccording to claim 1, wherein at least one of the rotating ring assignedto the coupling plug and the rotating ring (4) assigned to the couplingsocket are in an operative connection with the drive shafts of the ballvalves by way of ring gears or pinion gears.
 5. A coupling for cryogenicmedia according to claim 1, wherein a force can be applied to therotating ring assigned to the coupling plug.
 6. A coupling for cryogenicmedia according to claim 5, wherein the force applied to the rotatingring assigned to the coupling plug is in the direction of the rotatingring assigned to the coupling socket.
 7. A method of refueling a motorvehicle, comprising: forming a coupling connection using a couplingaccording to claim 1; and dispensing a refueling media.
 8. A method ofrefueling a motor vehicle according to claim 7, wherein the refuelingmedia is a cryogenic media.
 9. A method of refueling a motor vehicleaccording to claim 7, wherein the refueling media is liquid hydrogen orliquefied natural gas.